1. Field of the Invention
The present invention is related to a rotary encoder which detects a change of a physical quantity involved in a rotation of a rotor with respect to a stator and measures a rotation angle of an object based on the change.
2. Description of Related Art
A guide detection type rotary encoder has a stator installing a transmission winding and a reception winding, and a rotor installing a flux coupling winding magnetically combined with the stator with the windings (for example, Related Art 1). For a rotary encoder, it is required to further miniaturize a pitch of a reception winding due to a demand for a miniaturization and high precision of a micrometer, etc. mounting the rotary encoder.
The rotary encoder containing two tracks also has the following problems. In other words, in order to improve an accuracy of the rotary encoder, it is necessary to improve the accuracy of the two tracks at the same time. Also, the allowance for an absolute position measurement over the whole length area is small. Furthermore, when the allowance is increased, the accuracy of the rotary encoder deteriorates.                [Related Art] Japanese Patent Laid-open Publication H10-213407        